W83977F Datasheet, PDF (142/181 Pages) Winbond – PLUG & PLAY 1.0A COMPLIANT

W83977F/ W83977AF
10.6 Logical Device 4 (Real Time Clock)
PRELIMINARY
CR30 (Default 0x01 when PENKRC=1 at POR)
Bit 7-1 : Reserved.
Bit 0 :
= 1 Activates the logical device.
= 0 Logical device is inactive.
CR31
Bit 7-2 : Reserved.
Bit 1 : ENRNGCK -- > Enable I/O Range check
Bit 0 : FORIORD --> Forces LDN to respond I/O read
CR60, CR 61 (Default 0x00, 0x70 when PENKRC=1 at POR)
These two registers select Real Time Clock I/O base address [0x100:0xFFE] on 2 byte
boundaries.
CR70 (Default 0x08 when PENKRC=1 at POR)
Bit 7-4 : Reserved.
Bit [3:0] : These bits select IRQ resource for RTC.
CR71 (Default 0x00, read/write)
Bit 7-2 : Reserved.
Bit 1 : IRQLEV -- > IRQ Level
= 1: High; = 0: Low
Bit 0 : IRQTYPE --> IRQ Type
= 1: Level trigger; = 0: Edge trigger
CRF0 (Default 0x00)
RTC Mode Register
Bit 7-6 :
= 00 Select BANK0 of RAM
= 01 Select BANK1 of RAM
= 10 Select BANK2 of RAM
Bit 5-4 : Reserved.
Bit 3 : = 1 Lock CMOS RAM E0-FFh
Bit 2 : = 1 Lock CMOS RAM C0-DFh
Bit 1 : = 1 Lock CMOS RAM A0-BFh
Bit 0 : = 1 Lock CMOS RAM 80-9Fh
Note : Once set, bit[3:0] can not be cleared by a write; bit[3:0] is cleared only on Power-On Reset or upon a Hard Reset.
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Publication Release Date: March 1998
Revision 0.58